rump

noun

1. the hind part of the body of an animal, where the legs and back join, or the sacral part of a bird
2. a cut of meat, usually beef, from this part, behind the loin and above the round
3. the buttocks
4. the last, unimportant or inferior part; mere remnant
5. a legislature or other body having only a remnant of its former membership, as because of expulsions, and hence regarded as unrepresentative and without authority